Ozidoformate-isocyanate compounds and their uses

ABSTRACT

Disclosed are azidoformate-isocyanate compounds of the formula WHERE R is a polyvalent organic radical and x and y are integers from 1 to 100. The use of said azidoformate-isocyanate compounds to modify polymers, cross-link polymers, and adhere polymers to substrates selected from siliceous materials, metals and other polymer substrates is disclosed. Also disclosed are rubber tires reinforced with polyester tire cord which has been modified with an azidoformate-isocyanate compound.

United States Patent [191 Spurlin OZIDOFORMATE-ISOCYANATE COMPOUNDS ANDTHEIR USES [75] Inventor: Harold M. Spurlin, Wilmington, Del.

[73] Assignee: Hercules Incorporated, Wilmington,

Del.

[22] Filed: Aug. 26, 1971 [21] Appl. No.: 175,411

Related US. Application Data [62] Division of Ser. No. 860,034, Sept.22, 1969, Pat. No.

[52] 1.1.8. C1. 260/75 TN, 117/7 2, 152/359, 156/110 C, 260/77.5 CR.156/133, 156/314.

260/78.4 E, 260/78.4 D, 260/94.9 GB

[51] Int. Cl ..C08f 27/10 [58] Field of Search 260/75 TN, 78.5 T,260/94.9 GB, 77.5 AT, 77.5 CR, 78.4 E; 152/359 [56] References CitedUNITED STATES PATENTS 3,547,843 Suzuki 260/25 Breslow 260/349 1 Aug. 28,1973 3,558,669 l/l97l Breslow 260/349 Primary Examiner-Joseph L. SchoferAssistant Examiner-John Kight Attorney-John W. Whitson [57] ABSTRACTDisclosed are azidoformate-isocyanate compounds of the formula 6 Claims,No Drawings OZlDOFORMATE-ISOCYANATE COMPOUNDS AND THEIR USES Thisapplication is a division of my copending U.S. application Ser. No.860,034, filed Sept. 22, 1969, now U.S. Pat. No. 3,676,466.

This invention relates to a new class of organic compounds and tocertain uses for the new compounds. In particular this invention relatesto a new class of azidoformate-isocyanate compounds and their use inmodifying polymers, cross-linking polymers, and improving the adhesionof polymers to certain substrates.

The unique compounds of this invention are represented by the formulawherein R is a polyvalent organic radical and x and y are integersbroadly each being 1 to 100, preferably each being 1 to 10. Generally, Rwill be selected from the group consisting of the saturated andunsaturated aliphatic, cycloaliphatic, and aromatic hydrocarbon,hydrocarbon-oxy-hydrocarbon, hydrocarbon-thiohydrocarbon andhydrocarbon-sulfonyl-hydrocarbon polyvalent radicals and thecorresponding halosubstituted radicals. In preferred embodiments of thisinvention R will be an organic radical selected from the groupconsisting of radicals derived by the removal of two or more hydrogenatoms from alkanes, such as, for example, ethane, propane, butane,isobutane, pentane and its isomers, hexane and its isomers, octane andits isomers, decane and its isomers, dodecane and its isomers,octadecane and its isomers, and the like; cycloalkanes, such as, forexample, cyclopropane, cyclobutane, cyclopentane, cyclohexane,cyclooctane, and the like; alkylcycloalkanes such as, for example,ethylcyclohexane, methylcyclobutane, and the like; arylenes, such as,for example, benzene, naphthalene, biphenyl, and the like;alkyl-substituted arylenes, such as, for example, toluene, ethylbenzene,mand p-xylene, o-, mand p-diethylbenzene and the like;alkylenediarylenes, such as, for example, diphenylmethane, 1,2-diphenylethane, l,l-diphenylpropane, 1,3- diphenylpropane,2,2-diphenylpropane, and the like; dialkylcycloalkanes, such as, forexample, 1,2-, 1,3- and 1,4-dimethylcyclohexane, 1,2- andl,3-dimethylcyclopentane and the like; and the alkyloxyalkanes,aryloxyarylenes, alkaryloxyarylenes, alkaryloxyalkarylenes,aralkyloxyalkanes, aralkyloxyaralkanes, and the like; as well as thecorresponding thio and sulfonyl compounds, specific examples of whichinclude diethyl ether, propyl butyl ether, diphenyl ether,oxy-bis(pmethyl benzene), dibenzyl ether, diethyl sulfide, diphenylsulfide, dibenzyl sulfide, dibutyl sulfone, and the like compounds; andthe foregoing compounds with fluoro, chloro, bromo, and iodosubstituents. It will of course, be obvious to those skilled in the artthat R can contain other functional groups, which are substantiallyinert to the reactions in which these compounds are used, such as,esters, amides, etc. When an azidoformate-isocyanate compound of thisinvention is to be used as a coupling or cross-linking agent forpolymers, R preferably will be substantially inert to the coupling orcross-linking reaction.

Specific compounds of this invention represented by the foregoinggeneric formula include:

4isocyanatobutyl azidoformate S-isocyanatopentyl azidoformatemisocyanatophenyl azidoformate p-isocyanatophenyl azidoformate3-(4-isocyanatophenoxy)propyl azidoformate p-(2-isocyanatoethyl)phenylazidoformate 4-isocyanatocyclohexyl azidoformate4-(2-isocyanatoethyl)cyclohexyl azidoformate 1 l-isocyanatoheptadecylazidoformate 7,12-diisocyanatooctadecyl azidoformate 5-isocyanatononane- 1 ,9-diazidoformate4-azidocarbonyloxybutylif-isocyanatobutyl sulfone. Theazidoformate-isocyanate compounds of this invention range from liquidsto solids at room tempera ture and atmospheric pressure. They havecharacteristic infrared spectra, containing a strong azide band at about2140 cm, a strong carbonyl band at around 1735 cm and an isocyanate bandat about 2270 cm. The azidoformate radicals of the compounds of thisinvention become reactive when heated. As the temperature increases theoverall decomposition rate of the azidoformates increases. Theisocyanate portion of these compounds on the other hand, is quite heatstable, thus the azidoformate radicals can be decomposed by heatingwithout affecting the isocyanate radicals. The azide radicals readilyreact with receptive polymers and combine therewith. They also combinewith ethylenically unsaturated hydrocarbon groups in a variety ofcompounds. The isocyanate radicals can react at room temperature withwater, amines and alcohols.

The azidoformate-isocyanate compounds of this invention can be preparedby various methods for example, they can be prepared from thecorresponding hydroxy-carboxylic acid compounds by reaction withphosgene, thionyl chloride, sodium azide and finally heating torearrange the carbonyl azide to the isocyanate. This preparation can beshown as follows:

where R is as defined above. The first step in the preparation,comprising the reaction of the hydroxycarboxylic acid compound withphosgene, is usually carried out at a temperature of from about 0C. toabout 20C. in an inert solvent such as methylene chloride, ethylenedichloride, toluene xylene, etc. The second step in the preparationcomprising the reaction with thionyl chloride, is generally carried outat a temperature of from about 20C. to about C. with an excess of thethionyl chloride acting as a solvent or with some inert solvent such asone of the organic solvents recited above. The third step in thepreparation, comprising the reaction with the sodium azide, is generallyconducted at a temperature below C. in a mixed solvent such asacetone-water, ethyl alcohol-water, methylene chloride-acetone-water,benzene-acetone-water, etc. The final step in the preparation,comprising the rearrangement of the carbonyl azide to the isocyanate, iscarried out at temperatures up to 100C. in an inert solvent such asbenzene, toluene, etc.

As indicated above, this invention includes the use of the uniqueazidoformateisocyanate compounds in modifying polymers, cross-linkingpolymers, and improving the adhesion of polymers to various substrates.All of these modifications of the invention involve the reaction of theazidoformate portion or portions of the azidoformate-isocyanatecompounds with a receptive polymer. In this specification receptivepolymer means a polymer having in each polymer chain at least one andgenerally more than one monomer unit capable of combination reactionwith an azidoformate radical of a compound of this invention, wherebythe residue of the compound is chemically bonded to the polymer. Nearlyall polymers are receptive polymers. Preferred examples of a receptivepolymer include all types of hydrocarbon polymers including saturatedand unsaturated linear and non-linear, crystalline and amorphoushomopolymers, copolymers, terpolymers, and the like; for example,polyethylene, polypropylene, polystyrene, styrene-butadiene rubber,butyl rubber, natural rubber, polybutadiene, polyisobutylene,ethylene-propylene copolymer, cisl ,4-polyisoprene, ethylene--propylene-dicyclopentadiene terpolymer and the like; and blends of thesepolymers with each other and blends of these polymers with organicnonhydrocarbon polymers. In addition to the hydrocarbon polymerspreferred examples of a receptive polymer include a large number oforganic non-hydrocarbon polymers including homopolymers, copolymers,ter' polymers, and the like. Typical of these organic nonhydrocarbonpolymers are cellulose esters, such as, for example, celluloseacetate-butyrate, cellulose-acetatepropionate, cellulose acetate,cellulose propionate, cellulose butyrate, and the like; polyesters suchas poly- (ethylene glycol terephthalate), drying and non-drying alkydresins and the like; poly(alkylene oxide) polymers such as poly(ethyleneoxide), poly(propylene oxide) poly(ethylene oxide-propylene oxide);polyamides such as nylon, and the like; allyl pentaerythritolderivatives such as, for example, the condensate of triallylpentaerythritol with diallylidene pentaerythritol, esters of triallylpentaerythritol and drying oil fatty acids, and the like; poly(vinylalkyl ethers) such as, for example, poly(vinyl methyl ether) and thelike; poly(vinyl acetals) such as, for example, poly(vinyl butyral) andthe like; vinyl chloride polymers having a vinyl chloride content of atleast 10 mole percent such as, for example, poly( vinyl chloride), vinylchloridevinyl acetate copolymers, vinyl chloridevinylidene chloridecopolymers, vinyl chloride-vinyl acetal copolymers, such as, forexample, the vinyl chloride-vinyl butyral copolymers, vinylchloridevinylidene chloride-acrylonitrile terpolymers and the like;nitrocellulose; chlorinated natural rubber; sulfochlorinatedpolyethylene; polysulfide rubber; polyurethane rubber; poly (vinylacetate); ethylene-vinyl acetate copolymers, poly (vinylidene chloride);vinylidene chloride-acrylonitrile copolymers; ethylacrylate-Z-chloroethyl vinyl ether copolymers; poly(ethyl acrylate);poly- (ethyl methacrylate); poly[3,3-bis (chloromethyl)oxetane]; vinylmodified poly(dimethyl siloxane); polychloroprene;butadieneacrylonitrile copolymers; and the like.

The modified polymers of this invention resulting from the reaction ofthe azodiformate portion or portions of the azidofonnate-isocyanatecompounds with the above receptive polymers are both useful inthemselves and necessary intermediates in further modifications of thisinvention. The amount of azidoformateisocyanate compound used to modifya receptive polymer will depend upon the modification desired and thedesired end use. In general, however, the amount will be from about 0.01percent to about 40 percent by weight based on the weight of thepolymer. The resulting modified polymers are quite stable as long asthey are kept dry. They exhibit new and improved static properties,adhesion properties, launderability, etc.

Modification can be carried out by admixing the required amount ofazidoformate-isocyante compound with a receptive polymer and heating toa temperature sufficient to react the azidoformate portion or portionsof the compound with the polymer. This temperature will be in the rangeof from about C. to about 200C. In some cases it may be desirable to usean azidoformate-carbonyl azide intermediate which when heated rearrangesto form the corresponding azidoformate-isocyanate compound. The use ofthe intermediate is particularly advantageous in the presence of water.Since the carbonyl azide groups do not react with water, theintermediate can be used in the form of an aqueous dispersion. Then thewater can be removed by evaporation before heating to rearrange thecarbonyl a zide groups to isocyanate groups. The rearrangement occurs ata temperature in the range of from about 30C. to about 80C.

In one modification of this invention the azidoformate-isocyanatecompounds are used to cross-link, i.e. vulcanize, receptive polymers. Toeffect cross-linking the receptive polymer is first modified by reactionwith an azidoformate-isocyanate compound as described above and thentreated with a poly-functional compound which reacts with the freeisocyanate groups on the polymer. Various poly-functional compounds canbe used in this cross-linking, however, most preferred are thepolyamines such as diethylene triamine, mphenylene diamine,4,4-methylene dianiline, ethylene diamine, etc. and the polyalcoholssuch as 1,4- butanediol, ethylene glycol, tiethylene glycol,tn'methylolpropane, etc. When using one of these compounds the aminogroups or hydroxyl groups are believed to react with free isocyanategroups tying together, i.e. cross-linking the polymer chains. Instead ofusing a polyfunctional compound which is believed to react with the freeisocyanate groups, one may use water which converts some of the freeisocyanate groups to amines. The resulting amines are believed to reactwith the remaining isocyanate groups cross-linking the polymer chains.

In another modification of this invention the azidoformate-isocyanatecompounds are used to bond various polymers to certain substratesselected from siliceous materials, metals, and other polymers. A typicalexample of the bonding process of this invention is the bonding ofpoly(ethylene terephthalate) tire cord to rubber tire stock. The saidpolyester tire cord is first modified with the azidoformate-isocyanatecompound.

In so doing it is believed the azido portion or portions react with thepolyester leaving the isocyanate portion or portions free for laterreactions. Next the tire cord may be treated with a standard industrialdip which is compatible with the rubber in which the cord is to beembedded. The dip is a conventional tire cord adhesive essentiallycomprising a mixture of a phenol-aldehyde resin and a rubber latex. Ifdesired, the dip in the conventional tire cord adhesive can be omittedwith a proportionate decrease in adhesive strength. Finally, the thustreated tire cord is embedded in a commercial vulcanizable tire stockand cured. While polyester tire cords are mentioned various othersynthetic fibers useful as tire cords can be incorporated in rubber tirestock in accordance with this invention. Such other tire cords are forexample, polyolefins, polyamides, polycarbonates and rayon fibers.Improved adhesion of the synthetic fibers to rubber can be obtained bythe process of this invention no matter what the physical form of thesefibers. The tire cord can be treated with the azidoformate-isocyanatecompound by any conventional means, for example by dipping, spraying,brushing, or running the cord over a coated roll with a solution of theazidoformate-isocyanate compound in a suitable liquid. Exemplary ofsuitable organic solvents for the azidoformate-isocyanate compounds aretrichloroethane, acetone, ethylene dichloride, benzene, toluene, methylethyl ketone, etc. After the azidoformate-isocyanate is applied to thecord, the coated cord is heated to a temperature above the decompositionpoint of the azidoformate groups resulting in modification of the cord.Various amounts of the azidoformateisocyanate treating compound can beused. The optimum amount will depend upon the amount of modification ofthe cord desired, the specific azidoformateisocyanate used, etc. Ingeneral, the amount added, based on the cord, will be from about 0.5 toabout 2.0 percent by weight. As indicated above, the thus modified tirecord may be treated with a conventional tire cord adhesive. Thisadhesive comprises a mixture of a resin, preferably prepared fromresorcinol and formaldehyde, admixed with a latex, which is basically astyrene-butadiene-vinyl pyridine terpolymer. The vinyl pyridine contentof the terpolymer, is usually from about 5 percent to about 25 percent,the styrene content from about 5 percent to about 35 percent, and thebutadiene content from about 50 percent to about 85 percent. In somecases it may be desirable to add a small amount of a latex of thepolymer comprising the rubber tire stock. For example, if the rubbertire stock is an ethylene-propylene-diene terpolymer, it may bedesirable to add a small amount of a latex prepared from that terpolymerto the styrenebutadienevinyl pyridine terpolymer latex. If the rubbertire stock contains styrene-butadiene rubber there is, of course, noneed to add styrenebutadiene latex to the terpolymer latex. The latex isapplied to the modified tire cord by dipping, spraying, running the cordover a coated roll or other conventional procedure. The amount of latexadded will be from about 2 percent to about percent by weight of thecord. It is believed that the isocyanate groups on the modified tirecord react with the tire cord adhesive. The thus treated tire cord isthen embedded in a vulcanizable tire stock and cured under pressure. Thevulcanizable tire stocks in which the coated cord can be used as areinforcing medium include natural rubber, and synthetic rubbers such asstyrene-butadiene rubber, ethylenepropylenediene terpolymer rubbers,polybutadiene, polyisoprene, and mixtures and blends thereof withsuitable fillers, pigments, antioxidants, and cross-linking agents suchas sulfur, dicumyl peroxide, etc.

Another typical example of bonding a polymer to a substrate using anazidoformate-isocyanate compound is the bonding of an alpha-olefinpolymer such as polypropylene, to a glass substrate. Said glasssubstrate, such as glass cloth, is first treated with an amino silanecompound. In so doing, the silane portion of the compound reacts withthe substrate leaving the amine portion free for later reaction with theisocyanate portion of the azidoformate-isocyanate compound. Nextpolypropylene having been modified with an azidoformateisocyanatecompound so as to react the azidoformate portion or portions with thepolymer leaving the isocyanate portion free is placed in contact withthe above described treated glass. The free amine groups on the treatedglass react with the free isocyanate groups on the modified polymerforming a tight bond between the polymer and glass substrate.

Still another typical example of bonding a polymer to a substrate usingan azidoformate-isocyanate compound is the bonding of an alpha-olefinpolymer to a metal substrate such as a steel sheet. The steel sheet willfirst be treated with a priming agent, such as an amino silane compound,which possesses a group or groups which will bond to the metal surfaceleaving a free functional group or groups which are capable of reactionwith the isocyanate group or groups on the azidoformate-isocyanatecompound. The process of bonding the alpha-olefin polymer to the steelsheet can be carried out in various ways. For example, the sheet can becoated with a solution or suspension of the priming agent, allowed todry, then coated with a solution or suspension of theazidoformate-isocyanate compound, allowed to dry and finally contactedwith the alpha-olefin polymer at the decomposition temperature of theazide. By another method, the sheet can be coated with the primingagent, then contacted with both the azidoformate-isocyanate compound andthe alpha-olefin polymer at the decomposition temperature of the azide.By still another method, the priming agent, azidoformate-isocyanatecompound and alpha-olefm polymer can be deposited together on the sheetand then heated.

The substrates to which the polymers may be bonded in accordance withthis invention include siliceous materials such as glass, asbestos,sand, clay, concrete, brick, ceramic material, etc.; metals such asaluminum, cadmium, chromium, copper, magnesium, nickel, silver, tin,iron, titanium, zinc, etc.; alloys of the metals such as steel, brass,bronze, nickel chrome, etc. and including metals which have been surfacetreated with phosphates, chromates, etc. or on the surface of whichoxides have formed; and other polymers. By the term other polymers ismeant any polymer other than the polymer to which it is to be bonded.These substrates can be in various forms such as sheets, plates, blocks,wires, cloth, fibers, particles, etc.

The following examples will serve to illustrate the invention, all partsand percentages being by weight unless otherwise indicated.

EXAMPLE 1 This example illustrates the preparation of 5-isocyanatopentyl azidoformate.

To 85 parts of 6-chlorocarbonyloxyhexanoic acid was added 95 parts ofthionyl chloride dropwise over a period of 40 minutes. During "theaddition the reaction temperature dropped from 25C. to 15C. The reactionmixture was then warmed to 45C. for 2 hours and stirred overnight atroom temperature. The reaction mixture was then stripped under vacuum ofunreacted thionyl chloride to yield a yellow oil. This oil was vacuumdistilled to give 69.7 parts of 6-chlorocarbonyloxyhexanoyl chloride. Toa slurry comprising 79.5 parts of sodium azide, 150 parts water and 198parts acetone was added 65 parts of the 6-chlorocarbonyloxyhexanoylchloride dropwise with rapid stirring at a temperature of 5 to C. Afterstirring for an additional 2 hours at 0C., 200 parts of ice water and350 parts of cold benzene were added. The organic layer was separatedand washed three times with ice water. The resulting colorless productwas dried over magnesium sulfate and then refluxed at a temperature of80C. for 1 hour. After removing the solvent 51 parts of-isocyanatopentyl azidoformate was obtained. A typical infrared spectrumof this product displayed a strong isocyanate peak at 2270 cm, a strongazide doublet at 2,135 cm" and 2180 cm, as well as a strong carbonylpeak at 1,735 cm. The results of an infrared analysis of the product forprecent azido nitrogen and isocyanate is tabulated below:

Calculated Found Azido nitrogen 21.2 19.5

isocyanate 21.2 17 .9

EXAMPLE 2 This example illustrates the use of the 5- isocyanatopentylazidoformate of Example 1 in bonding polyester tire cord to rubber tirestock.

Poly(ethylene terephthalate) tire cord 1,000 denier and 3 ply underabout 500 grams of tension was passed twice through a trough containinga 5 percent solution of the 5-isocyanatopentyl azidoformate of Example 1in trichloroethylene. The cord was next passed through two ovens inseries at 200F. and 400F. Residence times in the ovens were 65 and 54seconds respectively. The cord dip pick-up was approximately 1 percentby weight.

The modified cord was next dipped in a resorcinolformaldehyde latexprepared as follows: To a solution of 0.24 part of sodium hydroxide in1928' parts of water was added 8.8 parts of resorcinol with continuedstirring until a complete solution was achieved. Then 12.2 parts of 37percent formaldehyde was added. The solution was aged for approximately5 hours at about 75C. and then added slowly to a mixture of 48 partswater and 195 parts of a commercial latex comprising a terpolymer ofstyrene, butadiene and vinyl pyridine, the monomers being present in aratio of approximately 50:70:15. The mixture was stirred slowly forminutes and its pH adjusted to 10.3 using concentrated ammoniumhydroxide. The resulting gray-violet latex contained approximatelypercent solids. The isocyanate-azidoformate modified cord was passedtwice through a trough of the above described latex under a tension of500 grams and then dried and cured for 54 seconds at a temperature of430F.

The thus coated cord was then vulcanized with a rubber tire stock in theform of "51s inch H-specimens. The

rubber tire stock has the following formulation:

Compounds Natural rubber (smoked sheet) Styrene butadiene rubberSemi-reinforcing furnace black Zinc Oxide Stcaric acid Polytrimethyldihydroquinoline Heavy me tar Benzot iazyl disulfide Tetramethyl thiuramdisulfide V Sulfur Parts The test specimens were cured for 45 minutes ata temperature of 307F. After several hours conditioning at roomtemperature of l-l-specimens were tested according to the procedure ofASTM D2l38-62T. An average (6 test specimens) of 36.6 pounds wasrequired to overcome the tire cord-rubber adhesion. A control specimentreated exactly the same as above except for the azidoformate-isocyanatetreatment gave an average of 16.8 pounds required to overcome thetire-cordrubber adhesion.

EXAMPLE 3 Compounds Parts SS/Nitrocellulose 112 sec. viscosity 60Terpene-derived alkyd resins 26 Diisobutyl adipate 0.25

The thus coated film was dried at a temperature of C. and heat sealed atC. for one-quarter of a second at 15 p.s.i. The nitrocellulose coatingadhered very tightly to the polypropylene film having a pell strength of105 pounds per inch. A control sample prepared exactly the same wayexcept for the treatment with the 5-isocyanatopentyl azidofonnate had apeel strength of 35 pounds per inch.

EXAMPLE 4 This example illustrates the preparation of pisocyanatophenylazidoformate.

To a slurry comprising 26 parts of sodium azide, 25 parts of water and47 parts of acetone was added 22 parts of p-chlorocarbonyloxybenzoylchloride with rapid stirring. After stirring for 3 hours at 3C. thereaction mixture was diluted with parts of ice water and 100 parts ofcold benzene. The benzene layer was separated, washed with ice water 3times and dried over magnesium sulfate. The dried solution ofpazidocarbonyloxybenzoyl azide was then refluxed for 6 hours in anitrogen atmosphere to give the pisocyanatophenyl azidoformate. Theresults of an infrared analysis of the product for percent azidonitrogen and isocyanate is tabulated below:

Calculated Found Nitrogen 20.6 19.5

lsocyanate 20.6 20.3

EXAMPLE 5 This example illustrates the use of a precursor of thep-isocyanatophenyl azidoforrnate, of Example 4, in bondingnitorcellulose lacquer to polypropylene film.

A sample of the biaxially oriented polypropylene film described inExample 3 was coated with nitrocellulose lacquer emulsion containing thepazidocarbonyloxybenzoyl azide described in Example 4. The compositionof the lacquer part of the emulsion was as follows:

Compounds Parts SS/Nitrocellulose l/2 second 25 Terpene derived alkydresins l Diisobutyl adipate 5 p-Azidocarbonyloxybenzoyl azide 4 Toluene20 Methyl isobutyl ketone 16 Amy] acetate 16 Non-ionic surface activeagent 4 polyoxyalkylene derivative of sorbitan monolaurate The abovelacquer was emulsified with water in a ratio of 2.5 parts of lacquer to1 part of water. The film coated with the above lacquer emulsion wasdried at 50C. in a stream of dry nitrogen and then heated to atemperature of 125C. to decompose the azides and form the isocyanates.The treated film was then heat sealed at 130C. for A second at psi. Thepeel strength of the nitrocellulose lacquer on the film was determinedto be 90 pounds per inch. A control sample prepared the same way exceptfor the addition of the p-azidocarbonyloxybenzoyl azide had a peelstrength of 35 pounds per inch.

EXAMPLE 6 To a slurry comprising 23.4 parts of sodium azide, 30 7 partsof water and 75 parts of acetone was added 25 parts of4-(3-chlorocarbonyloxypropyloxy)benzoyl chloride with rapid stirring ata temperature of -5C. After stirring for 3 hours at 0C. 150 parts of icewater and 125 parts of cold benzene were added. The benzene layer wasseparated, washed 3 times with ice water and then dried over magnesiumsulfate. The thus dried solution was refluxed for 7 hours. The solventwas removed from the solution to yield 3-(4-isocyanatophenoxy)propylazidofonnate. A typical infrared spectrum of this product displayed astrong isocyanate peak at 2,260 cm and a strong azide peak at 2,135 cm.The results of an infrared analysis of the product for percent azidonitrogen and isocyanate is tabulated below:

Calculated Found Nitrogen 16.0 15.6 loscyanate 16.0 15.2

EXAMPLE 7 This example illustrates the preparation of 4-isocyanatocyclohexyl azidoformate.

To a slurry comprising 33 parts of sodium azide, 50 parts of water andparts of acetone was added 22.5 parts chloride with rapid stirring at atemperature of 0C. After stirring for 2 hours at 3C. 200 parts of icewater and parts of cold benzene were added. The benzene layer wasseparated, washed with water 3 times and dried over magnesium sulfate.This 4- azidocarbonyloxycyclohexanecarbonyl azide solution was thenheated to reflux for 5 hours to form the 4- isocyanatocyclohexylazidoformate. Total yield was 86 percent of theoretical. The results ofan infrared analy' sis of the product for percent azido nitrogen andisocyanate is tabulated below:

Calculated Found Nitrogen 20.0 19.8

lsocyanate 20.0 19.5

EXAMPLE 8 This example illustrates the preparation of 11-isocyanato-l-n-hexylundecyl azidoformate.

To a solution of 30 parts of phosgene in 300 parts of drytetrahydrofuran was added 30 parts of l2- hydroxystearic acid at atemperature of 0C. After stirring at 3C. for 19 hours, the reaction waswarmed to room temperature and the solvent and excess phosgene removedunder vacuum. The resulting chloroformatecarboxylic acid was separatedand then refluxed with parts of thionyl chloride in 167 parts ofmethylene chloride for 8 hours. The reaction mixture was then strippedunder vacuum of unreacted thionyl chloride and solvent to give thebis-chloride. To a slurry comprising 40 parts of sodium azide, 25 partsof water and 175 parts of acetone was added 35 parts of the bischloridewith rapid stirring at a temperature of 0C. After stirring for 2 1%hours at 3C., 300 parts of ice water and 350 parts of cold benzene wereadded. The benzene layer was separated and washed three times with icewater and then dried over magnesium sulfate. The resulting solution wasgently refluxed for 5 hours in a nitrogen atmosphere. The benzenesolvent was then removed to yield the ll-isocyanato-l-n-hexylundecylazidoformate. The results of an infrared analysis of the product forpercent azido nitrogen and isocyanate is tabulated below:

Calculated Found Nitrogen 11.4 10.9

lsocyanate l 1.4 10.6

EXAMPLE 9 This example illustrates the cross-linking of anethylene-propylene copolymer with 5- isocyanatopentyl azidoformate.

One hundred parts of an ethylene-propylene copolymer, containing 40percent by weight of ethylene monomer and having a specific gravity of0.86, was placed on a two-roll mill maintained at 80C. and 6 parts of5-isocyanatopentyl azidoformate was added. After thorough blending onthe two-roll mill the mixture was removed and placed in a closed heatedmold for 30 minutes at a temperature of C. The thus of4-chlorocarbonyloxycyclohexanecarbonylv modified copolymer was thenheated in boiling water for one hour. The resulting product had beencrosslinked as evidenced by its insolubility in hot toluene. A controlsample treated exactly the same way except for the addition of-isocyanatopentyl azidoformate was completely soluble in hot toluene.

EXAMPLE This example illustrates the modification of a polyester withS-isocyanatopentyl azidoformate.

Test swatches 4 A by 10 inches of 100 percent poly- (ethyleneterephthalate) woven fabric, heat-set, spun dacron type 54 were dippedin a methylene chloride solution of S-isocyanatopentyl azidoforrnate.The methylene chloride solvent was evaporated to leave approximately 6percent add-on of the azide-isocyanate compound. The thus treatedswatches were sealed between glass plates and heated in an oven for 10minutes at a temperature of l90C. to cause reaction of the azidoformategroups with the polyester. The thus modified polyester fabric had thesame appearance as the unmodified fabric.

The free isocyanato groups attached to the modified fabric wereconverted to amine groups by laundering the modified fabric in a homewashing machine using a commercial detergent with a pH of 9. The thusmodified fabric having free amine groups was tested for water retentionby dipping samples of the swatches in water and draining. Waterretention in the modified fabric was approximately 10 percent more thanin the unmodified controls. Specular reflectance of a water drop placedon the modified fabric was observed to disappear in l to 2 minutes whilea water drop placed on an unmodified control fabric remained more than10 minutes.

Samples of the modified polyester fabric having free amine groups wascoated with an aqueous solution of polacrylic acid and cured for 10minutes at 130C. The amount add-on of polyacrylic acid was approximately1 percent. The polyacrylic acid (5 percent aqueous solution at 100F.)had a viscosity of 2.3 centistokes. To demonstrate the retention of thepolyacrylic acid on the fabric, samples of the modified swatches werelaundered 5 times in a home washer using a commercial detergent. Samplesof the polyacrylic acid modified fabric which had been laundered 5 timesand samples which had not been laundred were dyed under the sameconditions with malachite green. The laundered and unlaundered samplesexhibited the same color and intensity of dye. Control samples of thepolyester fabric which had not been treated with the azido-isocyanatocompound or with the polyacrylic acid could not be dyed. From the aboveit can be seen that the polyacrylic acid is actually chemically anchoredto the modified fabric.

EXAMPLE 1 1 This example illustrates the bonding of polypropylene toglass cloth using S-isocyanatopentyl azidoformate.

Twelve (12) ply laminates of glass cloth and polypropylene film wereprepared using 181 style electrical glass woven cloth, heat cleaned andhaving a weight of 8.9 ounces per square yard, and 5 mil film ofcrystalline polypropylene. Sheets of the glass cloth were first immersedin a 0.5 percent aqueous solution of I 'y-aminopropyltriethoxysilane,dried at room temperature and then heated in a forced air oven at C. for1 hour. The thus treated cloth was immersed in a benzene solutioncontaining 0.5 percent by weight of 5 isocyanatopentyl azidoformate for4 hours. The sheets of cloth were then removed, air dried and laid up toform the laminate by alternating plies of the treated glass cloth andsheets of the polypropylene film. The resulting assembly was compressionmolded at a temperature of 220C., for 5 minutes at contact pressure, 3minutes at a pressure of 500 p.s.i. and then cooled to 23C. under 500p.s.i. to form a If: inch thick laminate. A control laminate wasprepared exactly as described above except for the treating with the 5-isocyanatopentyl azidoformate. Test specimens 1 inch by 3 inches werecut from the laminates and tested for flexural strength according toAmerican Standard Testing Method D 790 in a 2 inch span at 0.05inch/minute crosshead speed. The laminate treated with theazidoformate-isocyanate compound had a flexural strength approximatelytwice that of the control.

EXAMPLE 12 This example illustrates the bonding of a polymer to analuminum panel using p-isocyanatophenyl azidoformate.

An aluminum panel l X 4 inches and 1116 inch thick was cleaned,degreased in trichloroethylene vapor, etched with dilute chromic acid,washed with distilled water and dried. The panel was then primed byimmersing in a 0.5 percent methanol-water solution of-y-aminopropyltriethoxysilane and dried in a forced air oven at 120C.for 2 hours. The thus primed panel was dipped in a colloidal suspensionof approximately 20-22 percent total solids crystalline polypropyleneparticles and containing about 0.75 percent by weight ofp-isocyanatophenyl azidoformate, in benzene. The coated panel was airdried, baked at a temperature of 230C. for eight minutes and thenallowed to cool. A control was prepared exactly as described aboveexcept for the addition of the p-isocyanatophenyl azidoformate. Thecoating on each panel was tested for adherence by scoring with a razorblade and then drawing the edge of a metal coin firmly across the thusscored surface. The coating on the panel containing theazidoformateisocyanate compound was not removed. The coating on thecontrol panel stripped easily from the aluminum substrate.

What I claim and desire to protect by Letters Patent l. A modifiedpolymer containing pendant isocyanate groups prepared by reacting apolymer, having in each polymer chain at least one monomer unit capableof combination reaction with an azidoformate radical, with from about0.0l percent to about 40 percent by weight based on the weight of thepolymer of an azidoformate-isocyanate compound having the formulawherein R is a polyvalent organic radical selected from the groupconsisting of saturated and unsaturated aliphatic, cycloaliphatic, andaromatic hydrocarbon, hydrocarbon-oxy-hydrocarbon,hydrocarbon-thiohydrocarbon and hydrocarbon-sulfonyl-hydrocarbonpolyvalent radicals and the corresponding halosubstituted radicals and xand y are integers from 1 to 100.

2. The modified polymer of claim 1, wherein the polymer ispolypropylene.

3. The modified polymer of claim 1 wherein the polymer is poly(ethyleneterephthalate).

4. The modified poly(ethylene terephthalate) of claim 8 wherein thepolymer is in the form of tire cord.

5. A process for making a modified polymer containing pendant isocyanategroups which comprises heating a polymer, having in each polymer chainat least one monomer unit capable of combination reaction with anazidoformate radical, in contact with from about 0.01 percent to about40 percent by weight based on the weight of the polymer of anazidoformateisocyanate compound having the formula wherein R is apolyvalent organic radical selected from the group consisting ofsaturated and unsaturated aliphatic, cycloaliphatic and aromatichydrocarbon, hydrocarbon-oxy-hydrocarbon, hydrocarbon-thiohydrocarbonand hydrocarbon-sulfonyl-hydrocarbon wherein R is a polyvalent organicradical selected from the group consisting of saturated and unsaturatedaliphatic, cycloaliphatic and aromatic hydrocarbon,hydrocarbon-oxy-hydrocarbon, hydrocarbon andhydrocarbon-sulfonyl-hydrocarbon polyvalent radicals and thecorresponding halosubstituted radicals and x and y are integers from 1to 100.

hydrocarbon-thio- UNITED STATES PATENT OFFICE (5/69) CERTIFICATE OFCORRECTION Patent N 3,755,260 Dated August 28, 1973 Inventor(s) Harold P(Case 28-29) It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Column 13 line 9 (Claim 4) "claim 8" should read claim 3 Signed andsealed this 18th day of December 1973 (SEAL) Attest: v

EDWARD M. FLETCHER, JR. RENE D 'I'EG'IMETZER Attesting Officer ActingCommissioner of Patents

2. The modified polymer of claim 1, wherein the polymer ispolypropylene.
 3. The modified polymer of claim 1 wherein the polymer ispoly(ethylene terephthalate).
 4. The modified poly(ethyleneterephthalate) of claim 8 wherein the polymer is in the form of tirecord.
 5. A process for making a modified polymer containing pendantisocyanate groups which comprises heating a polymer, having in eachpolymer chain at least one monomer unit capable of combination reactionwith an azidoformate radical, in contact with from about 0.01 percent toabout 40 percent by weight based on the weight of the polymer of anazidoformateisocyanate compound having the formula
 6. A process formaking a modified polymer containing pendant isocyanate groups whichcomprises heating a polymer, having in each polymer chain at least onemonomer unit capable of combination reaction with an azidoformateradical, in contact with an amount of azidoformate-carbonyl azidecompound which on heating rearranges to yield from about 0.01 percent toabout 40 percent by weight based on the weight of the polymer of anazidoformate-isocyanate compound having the formula